Environment and Health Issues We are living in a hostile world: depletion of ozone (臭氧) layer, global warming, air pollution, worldwide transmission of AIDS.... The fact that these environmental and health issues do not respect national boundaries implies that solutions to these problems only be global in scope. Concern about the state of the world's environment has grown domestically and internationally in the 1990s. The growth of Greenpeace as a movement, the limited success of Green parties in Europe, and legislation to halt the destruction of the environment in most developed democracies are concrete indications of the importance of this policy field. The essential problem for the environment, and many other international issues such as health protection, comes from the fact that it is a collective good. That such goods need to be preserved is often explained by what is called the 'tragedy of the commons'. In villages and towns where there are 'common lands', they are invariably overgrazed (过度放牧) by individuals who choose to keep their own lands under-utilized while they use the common land extensively. In other words, short-term individual, company, or state interests tend to prevail over common concerns and issues. Collective goods are not considered as important as the selfish interests of states, corporations, and individuals. In the same manner oceans are over fished and parklands destroyed. The advance of scientific knowledge and technology has brought immeasurable good and bad consequences for humankind. It has been responsible for improvements in health, nourishment, and physical labor, but its side effects are often dangerous. Environmentalists have pointed out many ways that humans are destroying the planet. They have shown that state borders do not count for very much with regard to environmental issues. Policy must, therefore, be developed at a level above the stale--in other words, internationally. Here are some examples of environmental issues that call for global action: Ozone The release of harmful man-made gases is destroying the ozone layer that protects the earth from ultraviolet rays (紫外线). In the mid-1980s scientists discovered that this thin layer of ozone encircling the stratosphere was being destroyed by the emission of chlorofluorocarbon (CFC) (含氯氟烃) gases and bromine from halons (哈龙) into the atmosphere. As the ozone layer is destroyed, it allows more ultraviolet light to reach the earth causing increased incidents of skin cancer, endangering marine life and possibly affecting the climate. In response the developed democracies signed and later amended a Montreal Protocol on Substances That Deplete the Ozone Layer, which freezes and eventually begins to decrease the use of CFCs and halon production. Global Warming Global warming is taking place at an alarming speed. This so-called 'greenhouse' effect is caused by the release of pollutants--CFCs, methane, nitrous oxide, and ozone--into the atmosphere and by the destruction of the rain forests. The destruction of forests reduces the earth's natural ability to extract carbon dioxide from the air. In other words, industrialization is causing the earth's climatic conditions to change. The so-called First World countries contain only 25% of the world's population yet consume 75% of its energy, 85% of its forest products, and are responsible for 75% of global warming. Country participants at the 1992 Earth Summit in Rio de Janeiro drafted conventions of climate change, biological diversity, and forests. Although governments were satisfied with the enunciated (确切表明的) goals, environmentalists criticized the protocols because they contained no targets or timetables. Renewable Resources The earth's vegetation (植被), too, is deteriorating. Forests are being destroyed and plant and animal species are becomi